The invention relates to a method of controlling an apparatus for producing products, in particular cigarettes, cigarette packs, plasters or plaster packs, having a programmable logic controllerxe2x80x94PLCxe2x80x94, an axis control system for controlling axes, in particular of drives, servo motors, conveying and/or cutting elements, and a visualization system for displaying processes and/or process parameters. The invention also relates to such an apparatus.
Production machines are known, for example machines for producing cigarettes or cigarette packs having a plurality of individually controllable drives or servo motors. Machines of this type regularly have a dedicated programmable logic control unit, by means of which these drives or their axes are driven. Furthermore, machines of this type have control units for axis control and a unit for visualizing processes or process parameters, this visualization unit being used as an interface between machine and operator, that is to say that the visualization unit also assists the operation of the machine.
In these conventional machines, the three aforementioned units, namely the programmable logic control unit, the axis control unit and the visualization unit, are implemented in physically self-contained appliances. The units regularly originate from different suppliers and are therefore not directly coordinated with one another. Although the units are linked with one another, this linking requires additional effort in the production of such machines, and also during the operation of the machines. The interchange of data is possible only by adapting the data from the various units to one another and therefore requires a certain xe2x80x9coverheadxe2x80x9d, that is to say additional outlay, in order to ensure the communication among these three components. In this way, the development and maintenance of such machines is made more difficult, and data processing is slowed down.
The invention is based on the object of improving such manufacturing machines and their control.
This object is achieved by a method of the type mentioned at the beginning by the PLC, the axis control system and the visualization system running on a common physical appliance, in particular a common hardware platform. An apparatus according to the invention of the type mentioned at the beginning is characterized in that the PLC, the axis control system and the visualization system are implemented on a common physical appliance, in particular a physical hardware platform.
Implementing the three components, PLC, axis control system and visualization system, on a common physical appliance means that the outlay on communication among these components is considerably simplified and reduced. Adaptation of the data from the various units is no longer necessary. This means that communication protocols between the various components can be dispensed with, which leads to a direct time gain and to faster data accesses. Furthermore, because of a more comprehensible data structure which is established, the result is a reduction of possible sources of error during the development, installation and maintenance of such machines.
Furthermore, an open structure of the control system is obtained, which permits a high degree of independence from the hardware used. By this means, the processes during the production of products can be coordinated quickly. By replacing the physical appliance, for example on the basis of a newly developed generation, an increase in the system performance overall is possible, and not merely an increase in the performance of individual components, which does not lead to an increase in the overall system performance.
In the present connection, the term xe2x80x9cproductxe2x80x9d is to be understood in the widest sense. It includes both the finished and the unfinished product, in particular including pre-products. The products in this sense pass through various processes, in particular along one or more conveying paths. Both the conveying speed and the processing speed within the individual processes are regularly very high in machines of this type. Exact co-ordination of the processes is therefore necessary if high product quality is to be achieved. The invention permits this exact and permanent co-ordination, even at high speeds.
This is because the increase in the data processing speed achieved by the integration according to the invention of the PLC, axis control system and visualization system in a common physical appliance, permits the individual servo drives to be co-ordinated with one another in a permanently regulated manner. To this end, use is made of sensors which monitor the products continuously, the drive axes being regulated on the basis of signals from these sensors. Manual monitoring, as n known machines, can therefore be dispensed with. Likewise, manual resetting of the servo drives can be dispensed with, since it is now carried out automatically with the effect of regulation.
A self-contained special feature consists in interrupting a treatment process, in particular spraying or gluing, of a material web or a product if a sensor indicates a planned and/or unplanned fault in the material web or the product. An interruption of this type is made deliberately only while the fault is being conveyed past a treatment element, in particular its nozzle, and not for the time taken to convey a complete product past. This achieves the situation where neither conveying elements are inadvertently glued or sprayed, which would lead to disadvantageous soiling of the machine, nor are individual material layers separated as a result of faulty gluing, which can lead to machine damage.
A further self-contained special feature is the deliberate ejection or deliberate separation of individual faulty products. As soon as a product has been detected as faulty by a sensor, this product is tracked from the sensor position to the separating element and then separated out individually and deliberately by the separating element. In the case of conventional machines, it is merely possible to separate out a relatively large number of products, containing a single faulty product, since products cannot be tracked individually because of too low a data processing speed.
The above special features, specifically controlling the drive on the basis of product monitoring, interrupting gluing only For the time taken to convey a fault past, and the deliberate separation of faulty products, are time-critical processes which, as a result of the high processing speeds, can be implemented only with fast data processing. The integration according to the invention of the PLC, axis control system and visualization system on a common physical appliance is the basis of fast data processing and therefore for these special features.